The scientists also found several species of rare plants and Chinese giant flying squirrels, which have striking red fur.

The team suggests the holes likely formed slowly over hundreds of thousands of years as underground water dissolved carbonate rock, such as limestone, under the surface. It's the same process that is frequently seen in other places around the globe—irregular landscapes commonly known as karst areas.

French cave explorer Jean Poutasi inspected one of the newly discovered sinkholes and called it "the world's most beautiful sinkhole," according to Chinese media.

Local officials hope that public interest in the sinkholes, along with the rugged beauty of the surrounding landscape, may attract tourists to the region. They also say they are starting to work on granting protection to the sites, which might contain geological records of past climates.

Sinkhole expert Randall Orndorff of the U.S. Geological Survey previously told National Geographic that a sinkhole is basically any collapsed or bowl-shaped feature that's formed when a void under the ground creates a depression into which everything around it drains.

Sinkholes can open up gradually or rapidly, sometimes swallowing buildings or vehicles and even causing deaths. Without advanced sensing techniques like ground-penetrating radar, sinkholes often leave little indication on the surface as they form, until the soil above them collapses. Occasionally, however, they are preceded by cracks or slumping.

Sometimes landslides are mistaken for sinkholes, but a true natural sinkhole requires that a void form from below. Certain human activity—such as construction or poor water management—can also cause artificial sinkholes, sometimes to devastating effect.